Key Takeaways
- Two-way SMS on an Android gateway is inbound to the SIM plus a webhook or inbox your staff actually watches.
- The phone must stay online. Doze and a dead charger look like “customers never reply.”
- Separate STOP (marketing) from YES/NO (bookings). One policy document, one parser.
- Do not run promo and support on the same thread you use for portal OTP.
- You bring the phone and airtime. Replies still occupy the radio; outbound still meters volume.
Android sms gateway two way sms inbox practice is a charged phone, a keyword policy, and a server that does not lose “I’ll be 10 late.” Pillar: two-way SMS. Auto-reply: STOP / auto-reply.
You bring the Android and operator credit. We meter devices and volume. Developer Center.
Inbound
YES — keep the slot
Inbox is a radio that must stay awake
Inbound SMS lands on the SIM first. If the app is frozen, your webhook is empty and the host stand is blind. Doze · setup.
An inbox nobody pages at 19:30 is a museum exhibit. Wire the webhook or staff the phone.
Practices that survive Friday night
| Practice | Why |
|---|---|
| Dedicated inbound MSISDN | OTP and promo do not pollute the thread |
| Keyword matrix | STOP ≠ cancel booking ≠ HELP |
| Webhook + human fallback | CRM first; phone UI as break-glass |
| Quiet hours on promo only | Table-ready / “I’m late” still deliver |
| Event-id unique | Retries must not double auto-reply |
Messaging industry context: GSMA. Local consent law still wins.
STOP vs operational replies
Persist marketing opt-out. Blacklist. Do not apply STOP to a viewing-cancel keyword without a written rule. STOP handling.
message.received
{
"id": "evt_01K2F8QW3N4RXB7M",
"type": "message.received",
"createdAt": "2026-08-12T14:04:09Z",
"apiVersion": "2026-08-12",
"data": {
"message": {
"id": 41822,
"number": "+14155552671",
"text": "Yes, please reschedule to Thursday.",
"status": "Received",
"deviceId": 3,
"receivedAt": "2026-08-12T14:04:09Z"
}
}
}Verify HMAC on your server. Server webhook · /webhook.
One MSISDN, one job
Listing promo on the same number as “your table is ready” trains people to mute you. Restaurant templates.
What you store
Inbound bodies are personal data. Keep a retention policy. Data retention.
Inbound is not free outbound
Auto-replies are sends. Free: 300 SMS lifetime. Developer: 25,000/year. Starter/Pro/Business uncap platform volume, devices 2/5/15. Pause on Free/Developer at allowance. No unlimited carrier SMS.
Checklist
- Inbound SIM plugged in; daily canary reply from a staff phone.
- STOP vs ops keywords in one table.
- Webhook signature + event-id unique.
- OTP MSISDN not in that inbox.
Next steps
Send a test inbound, watch the CRM row, reply once, confirm one outbound bubble. Downloads.
Related product pages
Jump to the live product docs for this topic—not another long-form article.
- two-way SMS inboxReplies on your SIM
- SMS auto-reply and STOP keywordsOpt-out and keywords
- SMS API documentationLive endpoint reference
- device and SMS volume pricingPlans and allowances
